Orienting instrument



l oct. 23,1945. y. P. CROSMAN f 2,387,647

ORIENTING INSTRUMENT Filed June 16, 1945 -V 2 Sheets-'Sheet l A r-mIIr-l Oct. 23, 1945. .`P. cRosMAN Y l 2,387,647 v1 ORIENTING INSTRUMENTFiled June 16, 1945 A2 `Sheets-Shee'f. 2

IN VENTOR Patented Oct. 23, 1.945

UNITED sTATEs PATENT OFFICE ORIEN TIN G INSTRUMENT Loring PickeringCrosman, South Orange, N, J., asslgnor to Monroe Calculating MachineConrpany, Orange, N. J., a corporation of Delaware Application June 18,1943, Serial No. 491,259*

( Cl. S3-224) 7 Claims.

The invention relates to orienting instruments, whereby a vehicle, suchas an airplane, or land vehicle, may be brought to rest'in a series ofgiven differentlyV oriented positions, as is necessary` in verifying thereadings of .a compass mounted in the vehicle and subject to variationscaused by the presence of disturbing local influences.

Commonly, vehicles have been oriented by marking out upon the ground aneight sided rose, oriented tothe cardinal and inter-cardinal points ofthe compass,` the `vehicle being aligned with the lateral markssuccessively. In each aligned position, the compass compensators areadjusted to bring the correct point to the lubber line. The laying outof such a roseis a complicated and time consuming operation and theaccurate alignment of the vehicle is troublesome, all of which may beavoided by the use of the present invention.

VAccording to the invention, a master compass is provided with meanswhereby it may be held 'at a sufficient distancefrom the vehicle to beoutside of the iield of local disturbance, and in given angular relationto the vehicle. Thus the readings of the two Compasses may be compared,in` diiferent positions of the vehicle determined by the bearings of themaster compass, and the vehicle compass compensated as may be necessary.

The `inventionconsists in the novel construction and combination ofparts, as set forth in the appended claims. l

In the accompanying drawings, illustrating the invention: A

Fig. 1 is a diagrammatic view, illustrating a preferred method ofchecking the angular relation of the instrument to a vehicle.

i Fig. 2 is a transverse vertical section through the instrument. e

Fig. 3 is a top plan view of the instrument.

Fig. 4 isa bottom plan view of the same.

In Figure 1 of these drawings the numeral I designates a car or jeepupon which a magneticcompass is. assumed to be mounted, and 2 is theorienting instrument designed for' attachment to the car by parallelcables 3, 3. The instrument comprises an elongated frame `2 upon which amagnetic compass 4 is mounted, the cables 3, 3 being secured .to theframe and led over pulleys '5, 5 mounted in the ends of the frame.

The free ends of the cables are designed for removable attachment tofixtures 6, upon the vehicle, these nxtures being located parallel tothe longitudinal axis ofV the vehicle and` spaced apart by an intervalequal to the length of the frame 2. Thus when the instrument is heldwith the cables 3, 3 fully extended, these cables form two sides of aparallelogram, the other sides `of which are formed by the longitudinalaxes of the instrument and of the vehicle.

In use, the Vehicle is driven in an arc about the operator at theinstrument, being stopped upon signal from the operator as it cornesapproximately to position facing one of the cardinal or inter-cardinalpoints. During the movement of the vehicle the operator, holding theframe 2 in both hands, turns, keeping an even tension upon the cables.The vehicle having stopped, Vthe operator, by reference to the lubberline of compass 4, informs the assistant in the vehicle how far theorientation diiers from the desired point (as minus two degrees, or plusone degree), whereupon the assistant adjusts the compensators to bringthe vehicle compass into conmade up of strands of non-*magnetic metalwoven in such a manner as to provide againsty stretching and to reducethe tendency to kink. Any of the commercial cables which meet theserequirements may be used for the purpose.

Preferably, as seen in Figs. 2 and 3, the cables are attached to a reel'l rotatably mounted upon the frame 2 by means of rollers 8 engaging anannular track formed in the reel and supported from a plate 9,'fastenedto the frame, the cables being attached to opposite sides of the reel. Aspring brake (not shown), of conventional design may engage the reel,and be released by the operator as the cable is wound upon the reel.

When the instrument is used over a considerable period of time itwillneed occasional checking up to determine whether the cables continueto keep it in parallel relation to the vehicle. For the purpose ofmaking any corrections necessary to bring the instrument intoparallelism means are provided for adjusting the cables and the compass4 relatively to each other. Obviously this could be done by adjustingone `or both of the cables to change the effective length thereof or, asherein shown, by adjusting the unit of .the compass upon which thelubber line is marked relatively to the frame 2. Where cornpasses areemployed having a card located close to the upper surface of the casing,the adjustable unit may consist of an annular plate having the lubberline marked upon the inner marginal face thereof, and the compass casemay be fixed in the frame 2. However, Compasses of this characterusually have a card spaced some distance below the upper face or glassof the casing, and the lubber line consists of a vertical mark on theinterior wall of the casing. To provide for this condition the compassis rotatably mounted as shown in Figs. 2 and 4, an annular plate IIbeing secured to the frame 2 by bolts passing through slots in theplate, and adjustably secured upon the frame by means of nuts l2.

The compass case is formed with a flange, overlying the inner marginalportion of the annular plate and is secured rigidly to the plate bymeans of clamps I3, the compass bowl extending downwardly into a centralopening through frame 2 and through the opening in the plate 9. When itis desired to adjust the compass the nuts I2 are loosened and plate l!is rotated by means of a threaded rod I4 engaging the threaded seat of apost I5 pvotally mounted in plate I I.

For the purpose of determining when the compass 4 has been brought intoproper relation to the vehicle two diametricall-'y opposite spacedsights or posts I6, II may be provided, these posts being xed in theannular plate II and extending upward therefrom. The tops of the postsI5 are marked as by the provision of a notch, these notches beingdesigned to be brought into line with two fixtures or sights I'I, i8upon the vehicle (Fig. 1), these xtures being located parallel to thetransverse axis of the vehicle. A cord IS maybe stretched between thepoints I6, I6, I8, I1, being attached, for instance, to xture I'I,extended above a mark of fixture I8 and engaged with the notches of theposts I6, I6, .the free end of the cord being weighted. By adjusting thecompass 1:'. until cord I9 shows that the four sighting points I6, I5,Il and I8 have been brought into line, the lubber line of compass 4 willbe accurately located relative to the major axis of the vehicle. Thecheck-up having been made cord I9 is removed, and the instrumentoperated as previously described.

It will be obvious that other methods of verifying the bearing ofcompass 4 may be employed, but the above described arrangement isextremely simple and easily applied.

I claim:

l. Means for orienting a vehicle provided with a magnetic compass havingthe usual compensator, comprising an elongated portable frame havingmounted thereon centrally of its length a master magnetic compass andmeans adapted for connecting opposite ends of said frame with certainspaced points of the vehicle to maintain in parallel relation thelongitudinal axes of said frame and of said vehicle throughout a seriesof differently oriented positions of said vehicle, said means includingexible cables carried by and extending from opposite ends of said frameand of length sufficient to locate the master compass of said frameoutside the field of local disturbances to which the compass of saidvehicle would be subject.

2. Means for orienting a vehicle provided with a magnetic compass havingthe usual compensa.-

tor, comprising an elongated portableframe having mounted thereoncentrally of its length a master magnetic compass and means adapted for.connecting opposite ends of said frame with certain spaced points ofthe vehicle to maintain in parallel relation the longitudinal axes ofsaid frame and of said vehicle throughout a series of differentlyoriented positions given the vehicle, said means including flexiblecables carried by and extending from opposite ends of said frame and oflength sufficient to locate the master compass of said frame outside thefield of local disturbances to which the compass of said vehicle wouldbe subject, and means for verifying said parallel relation.

3. Means for orienting a vehicle provided with a magnetic compass havingthe usual compensator, comprising an elongated portable frame havingmounted thereon centrally of its length a master magnetic compass andmeans adapted for connecting the opposite ends of said frame withcertain spaced points of the vehicle to maintain in parallel relationthe longitudinal axes of said frame and of said vehicle throughout aseries of diierently oriented positions given the vehicle, said meansincluding flexible cables carried by and extending from the oppositeends of said frame and of length suiicient to locate the master compassof said frame outside the eld of local disturbances to which the compassof said vehicle would be subject, means to verify said parallel relationand means to compensate for variations from the parallel relation of thelongitudinal axes of said frame and of said vehicle.

Il. Means for orienting a vehicle provided with a magnetic compasshaving the usual compensator, comprising an elongated portable framehaving mounted thereon centrally of its length a master magnetic compassand means adapted for connecting the opposite ends of said framewithcertain spaced points of the vehicle to maintain in parallel relationthe longitudinal axesof said frame and of said vehicle throughout aseries of diierently oriented positions given the vehicle, said meansincluding flexible cables carried by and extending from opposite ends ofsaid frame and of length sufficient to locate the master compass of saidframe outside the field of local disturbances to which the compass ofVsaid vehicle would be subject, and means for verifying said parallelrelation including diametrically opposite spaced sights of said mastercompass adapted for alignment with the transverse axis of said vehicle.y

5. Means for orienting a vehicle provided with a magnetic compass havingthe usual compensator, comprising an elongated portable frame havingmounted thereon centrally of its length a master magnetic compass andmeans adapted for connecting opposite ends of said frame ,with certainspaced points of the vehicle to maintain in parallel relation thelongitudinal axes of said frame and of said vehicle throughout a seriesof differently oriented positions given the vehicle, said meansincluding ilexible cables carried by and extending from opposite ends ofsaid frame and of length su'icient to locate the master compass of saidframe outside the field of local disturbances to which the compass ofsaid Vvehicle would be subject, and means to compensate for variationsfrom the parallel relation of the longitudinal axes of said frame and ofsaid vehicle.

6. Means for orienting a vehicle provided with a magnetic compass havingthe usual compensator, comprising an elongated portable frame havingmounted thereon centrally of its length a master magnetic compass andmeans adapted for connecting opposite ends of said frame with certainspaced points of the vehicle to maintain in parallel relation thelongitudinal axes of said frame and of said Vehicle throughout avseriesof differently oriented positions given the vehicle, said meansincluding flexible cables carried by and extending from opposite ends ofsaid frame and of length sufcient to locate the master compass of saidframe outside the field of local disturbances to which the compass ofsaid vehicle `would be subject, and means to compensate for sator,comprising an elongated portable frame having mounted thereon centrallyof its length a master magnetic compass and means adapted for connectingopposite ends of said frame with certain spaced points of the Vehicle tomaintain in parallel relation the longitudinal axes of said frame and ofsaid vehicle throughout al series of differently oriented positionsgiven the vehicle, said means including flexible cables carried by andextending from opposite ends of said frame and of length sucient tolocate the master compass of said frame outside the field of localdisturbances to which the compass ofthe vehicle would be subject, and areel mounted upon said frame centrally of the length thereof, saidcables being oppositely Wound upon said reel, said reel having a handlefor control of said cables.

LORING PICKERING CROSMAN.

